A wide range of electronic devices include graphics processing units (GPU). Some examples of devices that may include a GPU include computer systems, gaming consoles, digital video disc (DVD) players, etc. A GPU may include graphics memory controllers that interface with local graphics memory devices. In a continuing effort to increase graphics subsystem performance, interconnect speeds between the graphics memory controllers and the local graphics memory devices are increasing. Training techniques may be used on these interconnects to adjust various parameters associated with data transfers between the graphics memory controller and the local graphics memory devices in order to allow increased clock frequencies.
Training operations may include manipulating a variety of parameters which may include driver impedance, termination impedance, reference voltage levels, data strobe timing, etc. Training operations may take significant periods of time and may prevent a GPU from delivering display data to a display device for those significant periods of time. It would be desirable to allow a GPU to deliver display data to a display device while training operations are being performed.
Similar training operations may also occur with other interfaces, including system memory interfaces. It would be desirable to allow data transfers while training operations are being performed.